| 摘要 |
PURPOSE:To improve self-discharge characteristic by constituting such that fibers are constituted with polyolefine-based resin with its inside and most of its surface layer being of different natures, with the resin material of the surface layer being more liable to be sulfonized than that of the inside, and mainly with the resin of the surface layer being sulfonized. CONSTITUTION:As a polyolefine-based resin fiber structure, its inside is made of a material relatively hard to be sulfonized or oxidized while the part near its surface is made of a material which can be relatively easily sulfonized, and with inside materials partially heat-fused in the area where fibers entangle with each other. Sulfonization near the surface layer necessary for hydrophile property is easy. The strength as a separator on the other hand can be maintained as the polyolefine-based resin inside is hard to be carbonized even if the material is immersed in fuming sulfuric acid or the like for relatively a long period of time in order to uniformly sulfonize. Thus, self-discharge can be reduced while providing hydrophile property. |
